/Engine/Source/Runtime/Landscape/Classes/LandscapeInfo.h
Retrieve the components currently loaded that overlap with a given "window" area
true if at least one overlapped component
bool GetOverlappedComponents ( const FTransform & InAreaWorldTransform, const FBox2D & InAreaExtents, [TMap](API\Runtime\Core\Containers\TMap)< FIntPoint, [ULandscapeComponent](API\Runtime\Landscape\ULandscapeComponent) * > & OutOverlappedComponents, FIntRect & OutComponentIndicesBoundingRect )